Polyolefin fibers are much to be desired, since they are more resistant to rot and mildew than are natural fibers. The polyolefins, per se, are not dyeable, however, since they contain no dye sites. One suggestion, graft copolymerization with a material which does contain dye sites, requires a treatment of the polyolefin to allow such graft polymerization. Hydroperoxidation is an excellent example of such treatment.
Previous attempts to oxidize polyolefins, however, so as to introduce hydroperoxides for graft copolymerization, have been accompanied by the overoxidation of the polyolefins accompanied by extensive lowering of the molecular weight (polymer degradation). Heretofore, the use of oxygen alone or radiation in the presence of oxygen to introduce hydroperoxide groups onto the polyolefin have been attempted, as has the use of oxygen and ozone in non-aqueous treating zones. In order to introduce sufficient hydroperoxide groups on the total mass of polyolefin being oxidized, the processes are carried out under conditions which result in the formation of peroxides, ketones, aldehydes, acids, etc., which cause destructive degradation of the resulting graft copolymer during formation of the fibers at extrusion temperatures. Thus, the very purpose of the oxidation (to produce useful, dyeable fibers) is frustrated.